[Harms technique of C1-C2 fixation with polyaxial screws and rods].
[Harms technique of C1-C2 fixation with polyaxial screws and rods].
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发表时间：
2005
影响因子：
0.4
通讯作者：
J. Štulík;T. Vyskočil;P. Šebesta;J. Kryl
中科院分区：
文献类型：
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作者：
J. Štulík;T. Vyskočil;P. Šebesta;J. Kryl
研究目的：Harms技术通过多轴螺钉和棒固定C1-C2是寰枢椎背侧固定的另一种选择。哈姆斯和梅尔彻在2001年发表了这种方法，但哈姆斯在1997年8月首次进行了手术。本研究的目的是评估第一个结果，并尝试在稳定寰枢椎复合体的广泛选择中为Harms C1-C2固定指定一个合适的位置。材料：2002年12月至2004年1月，我们对22名入住布拉格Motol大学医院第二医学院脊柱外科的患者进行了C1-C2的Harms固定。其中，18名患者纳入本研究，10名男性和8名女性，年龄在23至84岁之间（平均55.4岁），随访时间超过6个月。在14例患者中，我们使用Harms技术作为C1-C2的永久固定以实现寰枢关节融合术，在4例患者中，我们只应用了4至6个月，没有使用骨移植物或其替代物。我们采用永久固定治疗以下情况：寰椎骨折3例，牙髓基部IIA型粉碎性骨折3例，C2“其他”骨折2例，类风湿性关节炎寰枢垂直不稳1例，骨折牙髓畸形愈合1例，C1-C2复杂创伤4例。临时固定用于2例III型牙突移位骨折，2例固定寰枢关节旋转性脱位。只有一名患者在入院时表现出Frankel C神经缺陷的迹象，其余患者没有神经学上的发现。方法所有螺钉均在图像增强器下置入，均为侧向投影。首先我们将枕大神经在尾侧方向向C2方向用一个细的松脱器，用锥子标记C1侧块的入口点；用2.5毫米的钻头钻出一个穿过前皮质骨的导孔。在前后方向呈直线或略微收敛的轨迹，在矢状方向平行于C1后弓平面。我们尊重每位患者寰枢椎复合体的个体解剖差异。钻孔穿过整个椎体，除了骨多孔骨，其中只有后皮质骨用螺旋丝锥治疗。在这个阶段，大量出血通常是由沿C1-C2关节的硬膜外静脉丛周围的剥离引起的。通过快速插入螺钉和用螺钉头压迫静脉丛有效地控制了这一情况。通过双极电灼术控制出血是困难的，并且总是伴随着神经损伤的风险。螺钉厚3.5 mm，多轴头，双皮质插入C1侧块。随后，定位椎间C2-C3关节并触诊其椎管内侧边界。在距C2关节突内侧缘2mm和距尾侧缘5mm的交点处用锥子标记C2椎弓根螺钉的置入点。在x线增强器侧位投影下，钻孔大约平行于C1螺钉，即以20至30度的颅骨角度，直至并穿过前皮质骨。在横切面上，螺钉以20至25度的角度位于会聚方向。所有螺钉置入后，我们通过操纵患者头部或直接调整螺钉将前轴复合体复位到正确的解剖位置。然后根据所使用的仪器，应用连接3.0 mm杆并使用帽螺母或内螺母紧固。结果手术时间35 ~ 155 min，平均81 min。术中出血量50 ~ 1500ml，平均560ml。x线增强器使用时间0.4 ~ 2.6 min，平均0.9 min。寰椎共置入36颗螺钉；它们的长度为16至34毫米（平均30.6毫米）。所有螺钉在C1侧块内正确定位；两颗螺钉没有达到前皮质骨，一颗突出在前皮质骨上，但没有引起临床问题。在轴上插入36颗螺钉。其长度为28 ~ 36毫米（平均31.7毫米）。27枚螺钉通过峡部正确应用于C2前皮质骨，3枚螺钉太短而无法到达，5枚螺钉太靠近椎动脉管。其中，两例突入动脉管，但没有临床后果。其中一颗螺钉插入过中，进入椎管，但也没有临床反应。在C2内置入的36颗螺钉中，有3颗（8.3%）错位。C1-C2骨融合是14例患者的手术目标。术后6周时，2例患者达到，术后12周时，12例患者达到，术后6个月时，14例患者均达到。所有18例患者的C1-C2节段在12周时均稳定。4例患者报告在取出内固定物后，旋转运动受限10 - 25%。手术时间开始时比Magerl技术长，逐渐缩短至45 - 60分钟。当评估术中出血量和x线暴露时，也发现了类似的趋势。通过Harms和Melcher手术我们保住了枕下大神经。然而，与这些作者相反，我们没有切除寰枢关节。所有患者均实现了固体融合。在总共置入的72颗螺钉中，只有3颗（4.2%）被评估为错位；然而，当涉及到在C2插入36颗螺钉时，这是8.3%，这表明在C2插入螺钉更困难。我们没有观察到这些病例的任何临床后果。结论C1-C2内固定是一种稳定寰枢椎复合体的有效方法。它使我们能够在不损伤寰枢关节的情况下提供临时固定，并在螺钉和棒插入后复位椎骨，这是独一无二的。这些优点弥补了植入物的较高成本。
PURPOSE OF THE STUDY The Harms technique of stabilizing C1-C2 by fixation with polyaxial screws and rods is a further option for atlantoaxial fixation from the dorsal approach. Harms and Melcher published this method in 2001, but the operation had first been performed by Harms in August 1997. The aim of this study is to evaluate the first results and try to assign the Harms C1-C2 fixation an appropriate standing in the in broad range of options for stabilization of the atlantoaxial complex. MATERIAL Between December 2002 and January 2004 we carried out the Harms fixation of C1-C2 on 22 patients admitted to the Department of Spine Surgery, Motol University Hospital, 2nd Medical Faculty in Prague. Out of these, 18 patients were included in this study, 10 men and 8 women between 23 and 84 years of age (average, 55.4 years) followed-up longer than 6 months. In 14 patients we used the Harms technique as a permanent fixation of C1-C2 in order to achieve atlantoaxial arthrodesis and, in four patients, we applied it only for a period of 4 to 6 months without the use of bone grafts or their substitutions. We employed the permanent fixation to treat the following conditions: fracture of the atlas in three patients, type IIA comminuted fracture of the dens base in three patients, fracture of C2 categorized as "other" in two patients, atlantoaxial vertical instability in one patient with rheumatoid arthritis, malunion of the fractured dens in one patient, and complicated trauma to C1-C2 in four patients. The temporary fixation was used for type III displaced fractures of the dens in two and fixed atlantoaxial rotatory dislocations also in two cases. Only one patient showed signs of Frankel C neurological deficit on admission, the rest were without neurological findings. METHODS All screws were inserted under an image intensifier always in lateral projection. First we retracted the greater occipital nerve in a caudal direction towards C2 with a fine raspatory and, using an awl, marked the entry point in the C1 lateral mass; a pilot hole, reaching through the anterior cortical bone, was made with a 2.5 mm drill. It followed a straight or slightly convergent trajectory in an anterior-posterior direction and parallel to the plane of the C1 posterior arch in the sagittal direction. Individual anatomical variations in the atlantoaxial complex of every patient were respected. The hole was tapped through the entire vertebral body, with the exception of osteoporous bone in which only the posterior cortical bone was treated with a screw tap. At this stage profuse bleeding usually arose from dissection around the epidural venous plexus along the C1-C2 joint. This was effectively controlled by a quick insertion of a screw and compression of the venous plexus with the screw head. To control bleeding by bipolar electrocautery is difficult and is always associated with a risk of nerve injury. Screws 3.5 mm thick, with polyaxial heads, were inserted bicortically into the lateral mass of C1. Subsequently, the intervertebral C2-C3 joint was localized and its medial border in the spinal canal was palpated. The entry point for placement of a C2 pedicle screw was marked with an awl at the point of intersection at a distance of 2 mm from the medial border and 5 mm from the caudal border of the C2 articular process. Under an X-ray intensifier in lateral projection, a hole was drilled approximately parallel to the screws inserted in C1, i. e., at an angle of 20 to 30 degrees cranially, up to and through the anterior cortical bone. In the transversal plane, the screws were situated in a convergent direction at an angle of 20 to 25 degrees. After all screws had been inserted, we reduced the antlantoaxial complex in the correct anatomical position by manipulating the patient's head or by directly adjusting the screws. Connecting 3.0-mm rods were then applied and fastened by cap nuts or inner nuts according to the instrumentation used. RESULTS Operative time ranged from 35 to 155 min, with an average of 81 min. Intra-operative blood loss ranged from 50 to 1500 ml, with an average of 560 ml. The X-ray intensifier was used for a period of 0.4 to 2.6 min, with an average of 0.9 min. A total of 36 screws were inserted in the atlas; their length ranged from 16 to 34 mm (average, 30.6 mm). All screws were positioned correctly in the C1 lateral mass; two screws did not reach up to the anterior cortical bone and one protruded over it, but without causing clinical problems. Thirty-six screws were inserted in the axis. Their length ranged from 28 to 36 mm (average, 31.7) mm). Twenty-seven screws were correctly applied through the isthmus into the C2 anterior cortical bone, three were too short to reach it and five were placed too close to the vertebral artery canal. Of these, two protruded into the artery canal, but without clinical consequences. One screw inserted too medially passed into the spinal canal, but this also was without clinical response. Of the 36 screws inserted in C2, three (8.3 %) were malpositioned. Bony fusion at C1-C2 was the goal of this operation in 14 patients. At 6 weeks post-operatively, it was achieved in two patients, at 12 weeks in 12 patients and at 6 months in all 14 patients. The C1-C2 segment was stable at 12 weeks in all 18 treated patients. Four patients reported restriction of motion in rotation by 10 to 25 % after removal of the instrumentation. DISCUSSION Operative time, longer at the beginning than with the Magerl technique, gradually shortened to between 45 and 60 min. Similar trends were seen when intra-operative blood loss and X-ray exposure were evaluated. Using the Harms and Melcher procedure we saved the greater suboccipital nerve. In contrast to these authors, however, we did not resect the atlantoaxial joint. Solid fusion was achieved in all our patients. Of the total of 72 screws inserted, only three (4.2 %) were assessed as malpositioned; however, when related to the 36 screws inserted in C2, this was 8.3 %, which indicates that insertion of screws in C2 was more difficult. We did not observe any clinical consequences in any of these cases. CONCLUSIONS The Harms fixation of C1-C2 is a very effective technique for stabilizing the atlantoaxial complex. It enables us to provide temporary fixation without damage to atlantoaxial joints and to reduce the vertebrae after the screws and rods had been inserted, which is unique. These advantages compensate for a higher cost of the implant.